I created an iPhone/iPad app to teach place value in elementary school (and
maybe already kindergarden), see
https://itunes.apple.com/us/app/id568750442
–
this is free until November 1st, after that it will cost 99c. Currently it comes
in English and German, but an update containing also Spanish, French and other
languages is already submitted to the App Store. That version also makes it even
easier to grab and move tokens. I also submitted this as a Resource to the Math
Forum.

This material is based upon work supported by the
National Science Foundation under Grant DUE-0226284.
Any opinions, findings, and conclusions or recommendations
expressed in this material are those of the author(s)
and do not necessarily reflect the views of the
National Science Foundation.